What makes goldfish grow?
What factors influence the growth rate of a goldfish?
If you’ve got questions like these…
… I’ve got the post for you today.
We’re going to explore everything about goldfish growth!
Keep reading to learn more.
Why Would You want your Goldfish to Grow?
These are the 2 most common reasons:
- You’re a breeder and want to breed the next generation of your fish
- You want to see your little fish turn into big impressive fish
Many goldfish CAN get huge.
And they can also get huge rather quickly with the right husbandry.
As in, up to 18″ long!
But they don’t have to (and not all of them can).
How?
Well, this brings us to the next points:
How to Get Your Goldfish to Grow Large (Fast)
(Note: This works for most fish but not all goldfish have the genetics to get large no matter what you do.)
Throwing your fish in a pond is one method.
For those of us with fish indoors…
… There’s another method:
- Raise the temp gradually to the high 70’s to low 80’s F.
- Feed lots of small meals a day, 6-8 or feed 3-4 larger meals per day of high protein food such as bloodworms and earthworms. Brine shrimp is also good but it doesn’t have as much protein, probably better as a treat. Foods that contain at least 60% protein are the best. Live foods are fantastic.
- Change the water every day to remove hormones from the water – the larger the water change the better.
- Provide lots of foraging in between meals (green algae works great)
With this schedule, you will be BLOWN AWAY at how fast your fish can grow.
This has not only been found to be true by breeders trying to grow out fry…
One scientific study has even shown that feeding frequency for the goldfish’s granddaddy, the carp, have more significant growth at at least 4 feedings a day for young fish.
They can even have up to 24 small meals a day! (Though they should be really small.)
Side Effects of Growing Goldfish Very Fast
WARNING:
If you follow this method…
… The fish probably won’t develop to look as nice as it could.
For breeding purposes?
It won’t matter a hill of beans.
For the most beautiful fish?
You might not want to do it this way.
See:
Growing out fish quickly can throw off their proportions a bit. The overall aesthetic balance of the fish will be altered.
A well-groomed goldfish takes time, patience and a bit of finesse.
Such a fish would score higher at a show…
… And also live longer.
Yep, it’s true.
Growing your fish FASTER will shorten its lifespan.
The warmer water increases the metabolism (and also increases demand for food).
The higher metabolism means a shorter life.
Again, if you only want the fish to get to its reproductive stage quickly, this probably isn’t very important to you.
But if it’s your pet?
You may want to think twice about it.
That is, if you want to have them around for as many years as possible to come.
Look:
A goldfish does MOST of its growing in the first year of its life.
If you want them to grow big, that time needs to be spent packing them full of food and giving them lots of fresh water to remove the growth inhibiting hormones that would cause them to be stunted.
Frankly, to me it’s hard to say if you can avoid these side effects when trying to grow your goldfish.
Bigger fish usually have to be grown faster to maximize this short window of growth – or they won’t reach their full size potential.
Do Goldfish Have to Grow Large?
No, not at all!
(And some goldfish can’t grow large no matter what.)
There are some things to consider about large goldfish, which is…
… They require more space and food.
Which, in turn, means they cost more to own.
I’ve said it before and I’ll say it again…
Small goldfish can be just as healthy and happy as large ones.
And keeping your goldfish small (or having one that genetically won’t grow much) can be more convenient and cost-saving.
But how do you accomplish that?
- Related Post: Do Goldfish Grow to the Size of their Tank?
How to Grow a Smaller Goldfish
Basically, reverse the logic of how to grow them quickly.
- Rely on good biological filtration and/or live plants to take care of water quality rather than doing large frequent water changes.
- Feed one small meal once per day or once every other day
- Keep the water temperature unheated – around 65 is preferable.
- More fish will contribute to more growth inhibiting hormones in the water (not mandatory)
- Using a smaller aquaria concentrates the growth hormones (but is still not mandatory)
Keep in mind if you choose to use this form of husbandry with your fish, the effects may be long-lasting.
You can’t undo stunting.
But the good news?
Your fish will probably live much longer than the fast-grown large kind.
(The oldest goldfish in the world were ALL stunted.)
Smaller goldfish require less work, less space and less resources.
These are the pro’s and con’s to weigh when deciding how to grow out your goldfish.
- Related Post: Water Wisteria: Complete Care Guide (Planting & Growing)
Final Thoughts
Goldfish growth depends on a variety of factors.
By manipulating these factors, we can often control the final size and proportions of the fish.
Both methods used to produce larger or smaller goldfish can have lasting consequences.
This is part of the art of grooming goldfish.
What do you think?
Do you have any tips for getting your goldfish to get big (or stay small)?
Learn something new?
I invite you to participate by leaving your comment below!
One of my goldfish is not growing, while the others in the tank have all increased in size noticably. The fish I have were all purchased within a week of each other and within 1/4 inch of each other in size. I also noticed he has stopped foraging in the sand while my other fish still do. Sometimes he also sucks up food just to spit it out and I’m not sure if he’s eating enough. I feed them 3 to 4 times daily and a varied diet. I looked over him and there is nothing unusual on his body. He visually appears to be healthy. Water parameters are fine. There is an issue of bullying by one of the other fish, but my others appear to be well. Should I be concerned?
He might have flukes if he’s spitting food.
He is keeping away from some of my other fish though I’m not sure if it’s from the bullying. He isn’t rubbing against anything, his find aren’t clamped, and he isn’t gasping. His fins are not ragged either. How would I figure out if it’s flukes? I’m having trouble matching other symptoms. I’m also not sure if he’s stopped foraging because he’s avoiding the bully. Did a water test today, everything was fine but I did a 50% change in case there were parasites.
Microscopy is the only way to know for sure.
We moved into a house 2 years ago on the Gold coast QLD Australia with a large outside tank about 6+4 ft & about 18 inches deep. About 6 goldfish & we bought another 6. Now there are at least double that & a lot of little fish that look like guppies. I feed them everyday with dried flacky fish food. Water always looks dirty but have only lost about 3 fish in 2 years. Try to take out half the water every so often. Naturally the rain tops up the pool. Lots of lillies etc. Lots of baby gold fish. All good fun. Which the water was a lot clearer but then i suppose it would then make it easy for birds to eat them.
Thanks for sharing, Bluey! Sounds like you are doing great.
I would try to remove him/her into a hospital tank all alone. If you dont have a seperate tank for that purpose, either get one or use a large storage container that’s like plastic. Then, if the cause is bullying, they will feel more relaxed and you can observe it better. Also, if its sick, then it wont affect the others. I know my comment is late, but maybe this will help for future times.
When one of my fish arrived in the mail, I noticed he was missing one of his pelvic fins. He also had a tear in a caudal fin, which healed within a few days. Will his missing fin grow back? He seems healthy, but has a hard time swimming downward to get to the food.
The missing fin could be genetic, unless you saw it in the bag. Probably won’t grow back.
You really make it seem so easy with your presentation but I find this matter to be actually something which I think I would never understand. It seems too complex and very broad for me. I’m looking forward for your next post, I will try to get the hang of it
Is there a certain age that goldfish stop growing? Or do they just keep growing?
Generally, goldfish do most of their growing in the first year. They can continue to grow for years in a big pond. Hope that helps 🙂